This invention relates to a method of welding and more particularly to a method of welding utilizing both consumable and non-consumable electrodes blanketed with inert gas.
Consumable metallic electrodes shielded by inert gas are often referred to as metal inert gas shielded welding and known in the art by the acronym MIG welding and has been utilized widely in industry for high productivity welds.
Non-consumable electrodes, tungsten inert gas shielded welding is often referred to by its acronym TIG welding. TIG welding has been widely used in industry either with or without filler metal.
Either of these methods of welding may result in poor fusion when the thermal conductivity of the workpiece is high such as when welding copper or aluminum particularly when the joint is not preheated. Patents 3,122,629 and 3,328,556 describe a hot wire process of welding in which a non-consumable electrode forms an arc and filler wire is heated by an electrical current and fed into the arc produced by the non-consumable electrode. Heating the wire electrically provides some additional heat, but not enough to eliminate preheating when welding metals with high thermal conductivity.